I just recently acquired an 17 foot Old Town Canoe, that had been stored upside down for quite a few years. The bottom condition is very good with the usual scrapes and scratches you would expect on a used canoe and the inside is very new looking. The wooden beams, etc.

One problem and minor is that while it was stored, something must have been placed on the bottom surface because is has a distinct large dimple in the bottom near the center.

I put a couple of stobbs between one of the beams and the dark green bottom and it popped out after sitting in the direct sunlight for a few days. When we got this cold snap and the temperature dropped, the dimple popped back in.

Anyone know a simple way to condition the plastic bottom to keep the dimple from coming back? It doesn't affect the performance, it just looks odd.

MadisonBoats

04-17-2011, 03:13 PM

Sounds like someone may have placed a can of something caustic to plastic on top of it will in storage(?) I doubt there is a good fix for this issue if it is just an aesthetic problem. You would probably cause more damage trying to fix the dimple. If it were fiberglass; I would drill a hole in the center to allow a small-threaded rod to pass through. Then, I would place a small piece of chop-mat(fiberglass) and resin on each side. Cover with aluminum foil and put the rod through the hole and use a board on each side to clamp the patch with wing nuts pass through the board. This will compress the patch and remove any air voids. Let is set up for a day and remove. Then, place some masking tap on one side of the drilled hole and fill with a dab of finely diced fiberglass and resin. Let cure, remove the tap, sand the rough edges and apply a light coat of gelcoat that matches the color of the boat. Wetsand to blend and you will be ok. If this is a plastic canoe that been extruded; I am not sure you could use this approach and blend it as well.

whitefeather

04-17-2011, 03:56 PM

Shawn,

I believe it is a plastic, not sure how it was molded, but it was molded over a woven mat, probably kevlar. I know fiberglass when I see it as I have built things out of it. Its heavier than a fiberglass canoe that length also, 65 lbs. My kevlar and resin canoe, same length only weighed 45 lbs.

It doesn't look like it came into contact with anything caustic, just something heavy sitting on it for an extended period of time to where it may have stretched the plastic and now it has to assume the dimple position, one way or the other. Under load, like an heavy cooler it assumes its normal down position.

I guess I'll just have to get use to it, after all it was a freebie from a guy who was moving and didn't want to take it with him. I looked it up at Old Towne Canoes in Maine and it sold for $1500 new. So I guess I can't complain.

Just thought maybe someone had run into this problem and knew a good fix for it. I might just put a brace inside across the bottom and glue some outdoor carpeting down on the inside surface over it.

Man, when it gets wet, its gets real slick, fast, so it could use some non-slick surface to keep me from slipping and go swimming with the fishes! LOL!:biggrin:

Bfish

04-17-2011, 11:48 PM

It's not really affecting anything so I would leave it. If I were to fill it, I would look at vinyl mastic (roofing supplier), 3m brand is best. Basically it would be like putting a sticker of material over the spot. It won't match in color and your cutting job will be out of round too.

duckypaddler

04-20-2011, 07:26 AM

I just recently acquired an 17 foot Old Town Canoe, that had been stored upside down for quite a few years. The bottom condition is very good with the usual scrapes and scratches you would expect on a used canoe and the inside is very new looking. The wooden beams, etc.

One problem and minor is that while it was stored, something must have been placed on the bottom surface because is has a distinct large dimple in the bottom near the center.

I put a couple of stobbs between one of the beams and the dark green bottom and it popped out after sitting in the direct sunlight for a few days. When we got this cold snap and the temperature dropped, the dimple popped back in.

Anyone know a simple way to condition the plastic bottom to keep the dimple from coming back? It doesn't affect the performance, it just looks odd.

They call it oil-canning. Put some hot water in it and put it back out in the sun. If it popped out once, it will most likely do it again.:biggrin: And unless it's cracked & leaking stay away from vinyl mastic or doing anything else:eek:. I've also seen this where people strap down boats so tight that it causes similar damage, but is usually at tie down points and not in the middle.

Hope that helps

helix149

04-23-2011, 12:37 AM

Yup oil canning just like the previous poster said. Happens all the time to our whitewater kayaks. What I would recommend is putting the canoe on sawhorses or a couple chairs and placing a round metal weight on the dimple so it pushes it in the direction you want it to go. You then heat the other side of the boat up (carefully of course) with a hair dryer. If you can do this in a cool place such as basement or enclosed garage that will work the best. Once the dimple pops out apply just a little more heat to get it to set and then leave the setup to cool fully in the darkish cool place for a couple days. If that doesn't make the dimple stay away it is unlikely anything will. Good news is it shouldn't effect the boat much either way.